A wide variety of systems are known for producing fluids of economic interest from subterranean geological formations. In formations providing sufficient pressure to force the fluids to the earth's surface, the fluids may be collected and processed without the use of artificial lifting systems. Where, however, well pressures are insufficient to raise fluids to the collection point, artificial means are typically employed, such as pumping systems.
The particular configurations of an artificial lift pumping systems may vary widely depending upon the well conditions, the geological formations present, and the desired completion approach. In general however, such systems typically include an electric motor driven by power supplied from the earth's surface. The motor is coupled to a pump, which draws wellbore fluids from a production horizon and imparts sufficient head to force the fluids to the collection point. Such systems may include additional components especially adapted for the particular wellbore fluids or mix of fluids, including gas/oil separators, oil/water separators, water injection pumps, and so forth.
One such artificial lift pumping system is an electrical submersible pump (ESP). An ESP typically includes a motor section, a pump section, and a motor protector to seal the clean motor oil from wellbore fluids, and is deployed in a wellbore where it receives power via an electrical cable. An ESP is capable of generating a large pressure boost sufficient to lift production fluids even in ultra deep-water subsea developments. However, ESPs are typically confined by the amount of free gas content they can handle (especially at low intake pressures).
Another artificial lift pumping system is a multiphase pump (MPP). MPPs may, for example, include helico-axial, twin-screw and piston pumps, and are important for artificial lift in subsea oil and gas field operations (especially, in ultra deep-water subsea developments). MPPs can handle high gas volumes as well as the slugging and different flow regimes associated with multiphase production, including flows having high water and/or high gas content (as high as 100-percent water or gas). Using MPPs allows development of remote locations or previously uneconomical fields. Additionally, since the surface equipment, including separators, heater-treaters, dehydrators and pipes, is reduced, the impact on the environment is also reduced. A production deficiency, however, is that MPPs are typically not able to provide the high pressure required, without a large number of pumps aligned in series.
Accordingly, it would be advantageous to provide an artificial lift pumping system capable of handling a production fluid with various phase flow regimes while providing a sufficient pressure boost to lift the production fluid to a collection location.